Exhaust-steam-pressure control for injectors



Aug; 7, 1928.

R. J. VAN METER EXHAUST STEAM PRESSURE CONTROL FOR INJECTORS Filed larch 23, 1925 INVENTOR.

ATTORNEY ll tltlflfilllfitll Aug. '-7, 1928.

ll iTED STATES PATENT OFFICE.

ROY J. VAN METER,:OF STURGIS, MICHIGAN, "ASSIGNOR TO THE SUPERHEATER COM- PAINY, OF NEW YORK, N. Y.

EXHAUST-STEAM-IRESSURE CONTROL FOR INJECTORS.

Application fi1eri March 23,. 1925. Serial No. 17,496.

My invention relates to exhaust steam in jectors, and particularly to the type employed tor supplying feed water to locomotive boilers, typical forms of which are excnipliiied in United States Letters Patent hlo. l,3'l2,128, issued to .l. J. G. and R. l). Metcali'e on the 1st day o'l' June, 1920, and No. 1,442,532, issued to R. D. Metcalte, et al., on the ltlth day of January, 1923.

ltn injectors of this general type the n1otive tluid for normal. operation is exhaust steam supplied from the locomotive engine, which may or may not be supplemented by live steam from the boiler. During periods when the engine is not running the injector is operated, it necessary, by auxiliary live steam supplied directly itl'OIllllllQ boiler.

The characteristics of the exhaust steam injector are such that variations in the proportion of water and exhaust steam supplied thereto must be kept within reasonable limits and for this reason a close regulation oi? these elements is highly desirable. The regulation of the water supplied to the injector is con'iparatively simple, as any variations in the pressure under which the *ater i; supplied are slow and gradual, but the regulation ol the exhaust steam supply is a more ditlicult problem. Because oi the wide variations in the conditions under which the locomotive engine operates there is a very considerable variation in. the exhaust steam pressure, and, as will be easily understood, in the ordinary operation of the locomotive it is not always possible to have available exhaust steam at high pressure. The injector is therefore designed to work satisfactorily with moderate exhaust steam pressures, that is, pressures extending through a range of :tromlabout inches of vacuum to pounds per square inch pressure. Variations in the exhauststeam pressure in this range can be satisi actorily takencarebf by proper regulation of the injector. Under some conditions, however, for instance when the locomotive working under heavy loads and the engine is operating with fully open throttle and maximum cutoff, the exhaust pressure will. rise above that at which the injector will operate satisfactorily. Under conditions such as these the injector becomes abnormally sensitive and is likely to Fbreak and cease operating, that is, due to the improper proportioning of the steam and water til? 5.}; the injector the water velocity lost, the boiler check closes and the steam and water mixture is discharged through the injector overflow.

It is the object of my invention to eli1ninate the iossibility ol' the injector breaking because ojt cxcessve pressure of the ex haust steam supplied thereto, by automatically limiting the pressure which can be maintained in the exhaust steam supply line, and it is a further object to accomplish this by means which may be cheaply and. readily applied to existing; installations and which will have no undesirable eil'ect upon the back pressure a gail'ist which. the engine must work. Other and. Further objects will appear as the description proceeds.

In the accoin nuiying drawings I have shown two forms of apparatus suitable for Cttlfl'jx'lllglflll; my invention, Figure 1 being a diagrammatic tragmentary elevation partly insection ot a locomotive equipped with an exhaust steam injector to which my invention has been applied, and Figure 2 being a vertical section through, the exhaust pipe and a portion oi the cylinder saddle oil a locomotive showing another form of apparatus which may be employed in the exercise of my invention.

Referring;now to Figure l, the locomotive is ifndicat d generally at l, and has applied thereto th a water inlet 3, and di charging to the loco motive boiler through the teed pipe 1: and check valve 1;. Exhaust steam for the 11ormal operation of the a.-p )aratus is supplied through. conduit which is connected into the exhaust passage 6 oi? the cylinder saddle '2'. Live steam is supplied tothc injector through the supple]nentary steam pipe 8 and the amtiliary steam pipe 9 and thercgulal ion oil" the device is accomplished through the water valve 10 and nozzle control ll. he e various controls need not be described in detail, as the specific form of the exhaust steam injector forms no part of the n'escnt invention.

As has heretofore been mentim'ied, under certain working conditions the exhaust steam pressure in. the passage 6 ries to an undesirably high degree, and in order to prevent this higl'r pressure from atl'ectinu the operation of the injector I provide a reliei valve at the injector end of the supply pipe '5, designed to limit the pressure at which e .aust steam. may be supplied to the in exhaust steam injector 2, having lit jectorr Forthispurpose any suitable'form of relief valve may be employed and I have shown a conventional form comprising a main valve body 12 adapted to receive a valve seat 13, upon which there is suitably mounted a bonnet 14 carryng the valve 15,

i which is maintained on a seat by the spring ing a portion of the steam to escape throughthe outlet pipe 17 It is to be understood that. any type of valve .suitablefor this purpose :comes within the scope .of my invention andthat the regulation of the pressure may be" accomplished by any well known meansfas for instance the substitution of sp'ringsof different strength or the provision of means for regulating the tenslon on the spring employed.

In order -to utilize to the fullest extent the "steam'which is delivered into the outlet. pipe 17 and also to eliminate what might otherwise be an objectionable exhaust I prefer to place the discharge end of the pipe 17 under the extension of the locomotive stack 18 so that steam leaving the pipe 17 will be exhausted up the stack together with the steam issuing from the exhaust pipe 19, and

form a draft. creating means supplementing the action of the main exhaust. It is to be understood, however, that. this particular j disposition of the excess steam is not anessential factor in the exercisevofmy invention. i

In the modified form as illustrated in Figure 2,-exhaust steam is supplied to the injector from the exhaust passage 6' through the supply pipe ,5 which leads directly to the injector, and excessive steam pressure is prevented from reaching the injector by means which limit the maximum pressure which may be maintained in the exhaust passages 6".

In thegrform shown this means i. comprises a main exhaust pipe 19? having a nozzle outlet 20 through which all of the gsteam exhausted up the stack normally passes. Anauxiliary passage 21 is provided in the pipe 19 leading toa supplemental steam outlet. 22, the passage 21 being normally closed by a pressure relief valve of suitable type which in the present case has been shown as a duplicate of that already described in connection with Figure 1. In

general the operation of this form of the apparatus is similar to that already described, with the relief valve normally in closed position and opening when the pressure in the exhaust passage exceeds a certain pro-determined figure. It will be obvious that upon the opening of the valve any excess pressure will be relieved through the additional area of outlet opening which is brought into play.

Vhile in the form shown in both Figures 1 and 2 the secondary or auxiliary steam outlet is shown as a port at one side of the main exhaust nozzle, it is to be understood that any suitable form of opening such as an annulus around the main nozzle, or a centrally located jet may be emplo ed without departing from the scope of t e invention.

I claim:

1; The combination of a boiler, an injector supplying feed water thereto, means for supplying exhaust steam to said injector, and a pressure relief valve located in said means, said valve being normally closed and opening only when the pressure within said means exceeds a pre-determined figure. 2. The combination of a boiler, an injector supplying feed water thereto, a. flue gas outlet, an exhaust passage delivering draft creating steam through said outlet, a

connection from said pipe carrying exhaust steam to said injector, a pressure relief valve for maintaining the pressure of the steam supplied to said injector below a predetermined figure, and means discharging steam passing through said valve through said 7 outlet.

3. The combination of a boiler, an injcc tor supplying feed water thereto, an inlet pipe supplying exhaust steam to said inector, and a relief valve located in said inlet pipe and limiting the pressure maintainable in said pipe to a pre-determined figure. 4. Thecombination of a boiler, an injector supplyin feed water thereto, a flue gas outlet, an exhaust passage delivering draft creating steam through said outlet, 21 connection from said passage supplying exhaust steam to said injector, a pressure relief valve in said connection adapted to open only when the pressure within said pipe exceeds a pre-determined figure, and a pipe connected to the outlet of said valve and discharging steam passing therethrough through said outlet.

ROY J. VAN METER. 

